Electronic Detection of DNA Hybridization by Coupling Organic Field-Effect Transistor-Based Sensors and Hairpin-Shaped Probes

Abstract

In this paper, the electronic transduction of DNA hybridization is presented by coupling organic charge-modulated field-effect transistors (OCMFETs) and hairpin-shaped probes. These probes have shown interesting properties in terms of sensitivity and selectivity in other kinds of assays, in the form of molecular beacons (MBs). Their integration with organic-transistor based sensors, never explored before, paves the way to a new class of low-cost, easy-to-use, and portable genetic sensors with enhanced performances. Thanks to the peculiar characteristics of the employed sensor, measurements can be performed at relatively high ionic strengths, thus optimizing the probes’ functionality without affecting the detection ability of the device. A complete electrical characterization of the sensor is reported, including calibration with different target concentrations in the measurement environment and selectivity evaluation. In particular, DNA hybridization detection for target concentration as low as 100 pM is demonstrated.

An organic neurophysiological tool for neuronal metabolic activity monitoring

“…The OCMFET is a peculiar organic thin film transistor which, thanks to the double-gated structure and its simple transduction mechanism, has lately gained a considerable amount of interest in the sensing and biosensing field. Using this device, it was in fact possible to obtain high-sensitive and reference-less sensors such as, just to mention the latest works, sensors for monitoring electrogenic cells' electrical activity, 25 multimodal tactile sensors, 26 and DNA-based biosensors 27 . Its transduction mechanism relies on the modulation of the threshold voltage of the transistor caused by the presence of a charge, Q SENSE , in a specific part of the device called the sensing area ΔVTH∝−QitalicSENSECTOT,where C TOT is the sum of all the capacitances in the structure.…”

Field-Effect Transistor Biosensors for Biomedical Applications: Recent Advances and Future Prospects

“…For the first time, integrating organic-charge modulated FETs (OCMFETs) with hairpin-shaped probes not only enhances performance but also opens the future for a new class of low-cost, easy-operation and portable genetic sensors (Napoli’s group) [94]. OCMFET is an ideal candidate for performing detection measurements in the aqueous environment because of its physical separation between sensing area and organic semiconductor.…”

Organic Bioelectronics: Using Highly Conjugated Polymers to Interface with Biomolecules, Cells, and Tissues in the Human Body

“…[ 102 ] Instead, they are often conjugated either to an intermediate coating or layer, [ 103,104 ] or to metal electrodes that form part of the device. [ 99,105,106 ] Depending on the application, biorecognition elements can include antibodies, [ 107–109 ] nucleic acid sequences, [ 110,111 ] and enzymes. [ 112–114 ]…”

“…DNA detection has been extensively explored using conjugated polymer‐based devices. [ 110,111,366–369 ] Fast, low‐cost assays, without the need for sophisticated laboratory facilities and laborious labeling protocols, are desirable. The negatively charged phosphate groups on DNA backbones make it well suited to detection by potentiometric approaches.…”

“…Other approaches include incorporating hairpin‐shaped oligonucleotide sequences to form molecular beacons that hybridize to specific target sequences. [ 110 ] White et al. demonstrated a relatively uncommon floating gate organic transistor architecture, with an intermediate electrode that was hybridized with nucleic acid sequences.…”